1. Field of the Invention
The invention relates to a method and a device for processing 3D image data of a skull, wherein image data are selected or calculated from the 3D image data and are presented as 2D image data in one plane.
2. Description of Related Art and Introduction
There are a series of imaging methods which are used for presenting a human or animal skull such as, e.g. computer tomography methods, magnetic resonance tomography methods, positron emission tomography methods or the like. With such imaging methods, a multiplicity of 3D image data with extremely high information content is created from which the attending physician, depending on the purpose of the diagnosis or therapy, processes accordingly a desired partial quantity and presents it in a two-dimensional form as 2D image data. Thus, the multiplicity of 3D image data makes it difficult and time-consuming for the attending physician to make a diagnosis. The present invention is focused on methods for processing the image data of human or animal skulls which allow a faster diagnosis by the attending physician or personnel.
In particular in the case of accident-related skull injuries or infarcts, a fast diagnosis for enabling a fast medical intervention is essential. The accident-related skull injury is one of the most frequent reasons in the western world for physical and mental disability as well as death. It is estimated that in the United States of America at least 1.5 million persons per year suffer a skull injury. Approximately 51,000 thereof die per year, 290,000 are hospitalized and 1.2 million persons are treated and then discharged from the emergency room.
Depending on the clinical presentation of the patient and the medical history, a significant portion of these patients undergoes a computer tomography. Computer tomography has established itself as the reference standard for clarification of a suspected skull injury and enables a fast presentation and clarification of the injury pattern and potential complications within the skull.
While the diagnosis of a hemorrhage within the skull, the accident-related direct damage to the brain and the accident-associated infarct are the most important clinical questions which can be answered by means of computer tomography, the question concerning fractures in the skullcap and also in the skull base is the second most important one. Fractures in the skullcap and also in the skull base can involve the following complications: CSF fistula, neurovascular damages, meningitis, facial paralysis, deafness, laceration of vessels or dissections and shunt formations between arteries and veins. In regular diagnoses, fractures serve as indicators for a proximal associated injury such as, e.g. hemorrhages. In addition, fractures can also result in subsequent complications, in particular hemorrhages, even if there was initially no hemorrhage. Furthermore, depending on the respective case, the presence of fractures can have potential consequences in the legal and forensic sector, for example in the case of third party negligence, because for generating a skull fracture, a certain minimum level of violence is necessary. The newest generation of multi-detector computer tomographs offers a steadily increasing spatial resolution along the craniocaudal axis of the patient along with a proportionally increasing number of axial images. This improvement offers new possibilities for the insight into anatomical and pathological structures which have to be considered for the diagnosis. In daily clinical routine, these images are primarily diagnosed in the axial plane (in the imaging plane). Usually, the resolution provided by the imaging device is not fully utilized and for practical purposes, layers are calculated that are thicker than the device can offer. The maximum number of images examined during a computer tomography of the skull with modern scanners is more than 500 images in one plane if only the bone structure is examined and the soft tissue is disregarded. To date, three-dimensional reconstructions of the skull and the skull base are prepared only in exceptional cases if there are uncertainties during the initial diagnosis of the axial images or if a complex mechanism of injury is given which, based on the axial images, cannot be clearly explained by the diagnosing radiologist. However, the number of images and the complex anatomical situation of the skullcap imply that smaller fractures can be overlooked here.
Additional three-dimensional reconstructions of the skullcap and the skull base can help the radiologist to significantly increase the detection rate of fractures. In today's practice, however, this is usual only in special cases because 3D reconstructions require additional time of the radiographer and/or the radiologist and, of course, the evaluation of these 3D reconstructions is time-consuming. Furthermore, there is no standard and no evidence to indicate which of the available 3D reconstructions is the most suitable one for this purpose. Currently, there are only methods which generate a plurality of views of the skullcap so that many additional images have to be evaluated which, in turn, is time-critical.
Up to now, several studies have researched three-dimensional reconstructions of the facial skull and have dealt with the three-dimensional reconstruction of the skull base. There is no literature in existence which is exclusively concerned with the detection of skullcap fractures by means of computer tomography images. The 3D algorithms used for the above-cited studies include surfaced shading display (SSD) and volume rendering (VR) and for an exact view and alteration, need adequately powerful workstations and usually also the preparation of a film sequence in which the skull rotates about different axes and thus can be viewed from different sides. Again, the disadvantage is the time consumption required for this and the number of images which have to be generated for such a film.
It is therefore an object of the present invention to create an above-mentioned method and an above-mentioned device for processing the 3D image data of a skull, which allow a 2D overview presentation of certain parts of the skull which enables the attending physician or the diagnosing person to perform a particularly fast diagnosis. The required computation and cost expenditures shall be as low as possible. Disadvantages of the prior art shall be avoided or at least reduced.